Amanita phalloides, the mushroom suspected of fatally poisoning four elderly people at a Loomis, Calif., care home, is commonly called the death cap.

The death cap draws in mushroom hunters with its sturdy stem and smooth, bald top, ranging in color from bronze to greenish yellow, and then kills - it is almost singularly responsible for fatal mushroom poisonings worldwide.

“These mushrooms are very, very sexy,” said Dr. Todd Mitchell, a Santa Cruz physician who is leading a national study of an antidote to toxic mushroom poisoning. “They look very attractive in the field. They grow virtually side by side to chanterelles, and they look very robust. They smell quite sweet, and by all accounts are quite delicious.”

In Northern California, they grow abundantly during the fall and early winter, typically sprouting beneath live oak trees. The fungi, which contain a toxic protein that can cause permanent liver and kidney damage, sicken hundreds of people a year in California. On average, a half-dozen people suffer serious poisonings from the mushrooms annually and one or two die, said Dr. Kent Olson, executive medical director of the California Poison Control System.

Death caps are the primary suspects in the illnesses last month of six people at the Gold Age Villa in Loomis, four of whom have died.

Lilia Tirdea, a caregiver who cooked meals for residents of Gold Age Villa, picked wild mushrooms on the grounds of the care home, then cooked and served them in a gravy for dinner on Tuesday evening, Nov. 6.

By Thursday, nearly everyone who lived at the care home was terribly ill.

At first the home’s owner, Raisa Oselsky, who was not home when Tirdea served the mushrooms, suspected a rampant case of the flu. But after speaking with Tirdea, she realized that of the home’s six residents, only one had not eaten the mushroom dish. That person was fine.

Everyone else, including Tirdea, ended up in area emergency rooms.

Barbara Marie Lopes, 87, a spirited woman who raised three daughters on her own and worked for decades as an aircraft mechanic at the former McClellan Air Force Base, died Nov. 9. So did Teresa Jania Olesniewicz, 73, who was a physician in her native Poland before she came to the United States in the 1970s.

A week after the two women’s deaths, officials announced a third fatality tied to the mushroom gravy: Frank Warren Blodgett, 90. Last Thursday, Dorothy Mary Hart, 92, was the fourth to die.

Tirdea and one other person were recovering from the poisonings as of late last week, officials said.

In the quaint confines of Gold Age Villa, Lopes - whose memory was fading but who otherwise was fairly healthy - enjoyed watching TV, playing cards and keeping company with other residents and staffers, said her daughter Annette St. Urbain.

“They were all friends,” St. Urbain said. “Raisa and the rest of the staff were wonderful to my mother. We have no animosity toward them at all.”

Lopes, who stood just 5 feet tall, was raised on a farm in South Dakota, her daughter said. After moving to California, she took a job at McClellan inspecting aircraft.

“She was our own little Rosie the Riveter, small enough to fit into the nose cones” of planes to check for debris, said St. Urbain. “She was very proud of her work.”

Besides her children, her daughter said, Lopes’ great loves included big band music, dancing and solving jigsaw puzzles. Lopes had a strong faith in God and “above all, taught me forgiveness,” St. Urbain said.

Lopes had developed a tricky left knee, nerve pain from a bout with shingles and memory problems. She moved into Gold Age Villa nearly two years ago and was happy there, her daughter said.

On the Thursday evening after Lopes ate the poison mushrooms, St. Urbain got a call from Oselsky, telling her that Lopes was ill with what appeared to be the flu. Early the next morning, she heard from an emergency room doctor at Sutter Roseville hospital who said Lopes was near death from wild mushroom poisoning.

“I thought, ‘Mushroom poisoning? What?’ “ St. Urbain recalled. She contacted other relatives and headed to the hospital.

Lopes was conscious when they arrived, even joking, St. Urbain said. But within hours, she was dead.

“It was just a sad mistake. A lapse in judgment,” St. Urbain said of the circumstances of her mother’s death. “I feel terrible for everyone.”

Oselsky declined to talk to a reporter when approached at the care home last week. “We are having a hard time here,” she said, and referred all questions to her attorney.

“She is very, very distraught about the whole situation, very concerned for everyone affected and their families,” said the lawyer, James Hazen.

The California Department of Social Services has determined that the poisonings were accidental. Even so, Tirdea no longer is allowed to work in care facilities licensed by the state.

Regulators have deemed Tirdea a “threat to the health and safety” of clients, according to a report issued last week. But she will not face criminal charges. A police investigation concluded that “this was an accident,” said Placer County Sheriff’s Lt. Mark Reed.